1. Field of the Disclosure
This invention relates to image property detection.
2. Description of Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly nor implicitly admitted as prior art against the present invention.
Three dimensional (3D) television has recently been made available to the consumer, and it is expected that the amount of 3D equipment and programming will increase rapidly in the next few years.
3D television relies on a stereoscopic technique whereby pairs of images are captured by respective cameras which are laterally displaced (i.e. substantially in a horizontal image direction) by a certain distance, for example a typical spacing of a user's eyes. The pairs of images therefore represent slightly different views of the same scene; in general they will encompass the same items within the scene (except perhaps at the image extremities) but the relative positions of the items between the two images will depend on the distance of the items from the camera arrangement.
When the images are displayed, it is important that each of the user's eyes sees (at least mainly) a respective one of the image pair. In practice this is achieved in various ways, such as by the user wearing polarising, time multiplexing or colour-filtering spectacles, or by the television screen itself being provided with a special lens arrangement which diverts each of the two images to a respective eye position of the viewer. Of these, the colour-filtering technique, common in early attempts at 3D cinema, is not generally used in 3D television technology.
Returning to the 3D camera system, each of the pair of images is captured by an independent camera, with its own lens and image capture arrangement (for example a CCD arrangement). But in order to maintain the 3D illusion for the viewer, it is important that the two images of each image pair are closely matched in terms of their colour and related properties. Various colour parameters are available to the operator of a professional video camera or an external colour correction unit, such as the gamma, knee, white level and black level parameters, but the task of setting up a 3D camera arrangement is significantly more difficult than that of setting up a conventional (single) video camera because of the need not only to set the parameters correctly for the current scene, but also to set the parameters so that the two cameras forming the 3D camera arrangement generate images with identical image properties. In the case of a domestic video camera, the range of adjustments available to the user is much more limited, making it even more difficult to set the two cameras to provide identical colour properties.